Keyboard power button works but no trackpad or keys working.

Hi !

I have a 2006 Core Duo 1.83Ghz Macbook with logic board 820-1889-A and the keyboard (top case) is not working correctly.

The power button always works (On or Off with hard shut down) but as soon as the MAC is started or into OS X, the keyboard keys and trackpad are not working at all, no response whatsoever. (impossible to clear PRAM or boot with ALT button on startup)

The MAC is working well with USB mouse and keyboard plugged in.

I've read other topics on this subjects here, but all answers were related to a defective top case.

In my case, i've tried 4 different working top cases but with the same result, only power button is responsive.

I've cleaned the keyboard connector with canned air and they seem perfect, not dirty or bended and the plug is tight, nothing loose.

I'm thinking of a defective logic board, but i know that there are some technical king pins on Ifixit, so might as well try !

Thanks for you time.